<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script>
        let oWSet = new WeakSet();
//        oWSet.add(2);       //报错    不能存放基本类型，只能放引用类型的值
        oWSet.add({});
        console.log(oWSet);

    </script>
</head>
<body>

</body>
</html>